cc: Implement unified BeginFrame on aura

ui/compositor/compositor.h

Index: ui/compositor/compositor.h
diff --git a/ui/compositor/compositor.h b/ui/compositor/compositor.h
index bf61d29730e67aa70bd7c8533baa860a2335de42..1fc8e6f4788979e15164dbd0a2bb7eb39392e1fc 100644
--- a/ui/compositor/compositor.h
+++ b/ui/compositor/compositor.h
@@ -13,10 +13,12 @@
 #include "base/observer_list.h"
 #include "base/single_thread_task_runner.h"
 #include "base/time/time.h"
+#include "cc/output/begin_frame_args.h"
 #include "cc/surfaces/surface_sequence.h"
 #include "cc/trees/layer_tree_host_client.h"
 #include "cc/trees/layer_tree_host_single_thread_client.h"
 #include "third_party/skia/include/core/SkColor.h"
+#include "ui/base/compositor/compositor_begin_frame_observer.h"
 #include "ui/compositor/compositor_animation_observer.h"
 #include "ui/compositor/compositor_export.h"
 #include "ui/compositor/compositor_observer.h"
@@ -223,6 +225,11 @@ class COMPOSITOR_EXPORT Compositor
   void RemoveAnimationObserver(CompositorAnimationObserver* observer);
   bool HasAnimationObserver(const CompositorAnimationObserver* observer) const;
 
+  void AddBeginFrameObserver(
+      CompositorBeginFrameObserver* observer,
+      const cc::BeginFrameArgs& last_begin_frame_args_sent_to_observer);
+  void RemoveBeginFrameObserver(CompositorBeginFrameObserver* observer);
+
   // Creates a compositor lock. Returns NULL if it is not possible to lock at
   // this time (i.e. we're waiting to complete a previous unlock).
   scoped_refptr<CompositorLock> GetCompositorLock();
@@ -257,6 +264,7 @@ class COMPOSITOR_EXPORT Compositor
   void DidCommit() override;
   void DidCommitAndDrawFrame() override;
   void DidCompleteSwapBuffers() override;
+  void SendBeginFramesToChildren(const cc::BeginFrameArgs& args) override;
 
   // cc::LayerTreeHostSingleThreadClient implementation.
   void DidPostSwapBuffers() override;
@@ -286,6 +294,9 @@ class COMPOSITOR_EXPORT Compositor
   // Called to release any pending CompositorLock
   void CancelCompositorLock();
 
+  // Request scheduling of next BeginFrame to LayerTreeHost.
+  void SetChildrenNeedBeginFrames(bool need_begin_frame);
+
   gfx::Size size_;
 
   ui::ContextFactory* context_factory_;
@@ -295,6 +306,7 @@ class COMPOSITOR_EXPORT Compositor
 
   ObserverList<CompositorObserver> observer_list_;
   ObserverList<CompositorAnimationObserver> animation_observer_list_;
+  ObserverList<CompositorBeginFrameObserver> begin_frame_observer_list_;
 
   gfx::AcceleratedWidget widget_;
   scoped_ptr<cc::SurfaceIdAllocator> surface_id_allocator_;
@@ -319,6 +331,9 @@ class COMPOSITOR_EXPORT Compositor
 
   LayerAnimatorCollection layer_animator_collection_;
 
+  // Used to send to any new CompositorBeginFrameObserver immediately.
+  cc::BeginFrameArgs missed_begin_frame_args_;
+
   base::WeakPtrFactory<Compositor> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(Compositor);